78791938 has 4 divisors (see below), whose sum is σ = 118187910. Its totient is φ = 39395968.

The previous prime is 78791929. The next prime is 78791939. The reversal of 78791938 is 83919787.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83919787 = 7 ⋅11988541.

It can be written as a sum of positive squares in only one way, i.e., 70107129 + 8684809 = 8373^2 + 2947^2 .

It is not an unprimeable number, because it can be changed into a prime (78791939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19697983 + ... + 19697986.

Almost surely, 2^78791938 is an apocalyptic number.

78791938 is a deficient number, since it is larger than the sum of its proper divisors (39395972).

78791938 is a wasteful number, since it uses less digits than its factorization.

78791938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39395971.

The product of its digits is 762048, while the sum is 52.

The square root of 78791938 is about 8876.4822987488. The cubic root of 78791938 is about 428.7070191822.

The spelling of 78791938 in words is "seventy-eight million, seven hundred ninety-one thousand, nine hundred thirty-eight".